Spaceweather.com posts daily satellite images of noctilucent clouds (NLCs), which hover over Earth's poles at the edge of space. The data come from NASA's AIM spacecraft. The north polar "daisy" pictured below is a composite of near-realtime images from AIM assembled by researchers at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP).

Geomagnetic Storms:Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2014 Sep 07 2200 UTC

Mid-latitudes

0-24 hr

24-48 hr

ACTIVE

15 %

10 %

MINOR

01 %

05 %

SEVERE

01 %

01 %

High latitudes

0-24 hr

24-48 hr

ACTIVE

15 %

15 %

MINOR

25 %

20 %

SEVERE

20 %

15 %

Sunday, Sep. 7, 2014

What's up in space

When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.

WEAK IMPACT: According to NOAA analysts, a CME hit Earth's magnetic field on Sept. 6th at 1525 UT. However, the impact was weak and did not spark geomagnetic storms. Aurora alerts:text, voice

WEEKEND ASTEROID FLYBY: Today, a house-sized asteroid named "2014 RC" will fly through the Earth-Moon system almost inside the orbit of geosynchronous satellites. At closest approach, Sept. 7th at 18:18 UTC, the 20-meter-wide space rock will pass just 40,000 km over New Zealand. This diagram from NASA shows the geometry of the encounter:

There is no danger of a collision with Earth.

Asteroid 2014 RC was discovered on the night of August 31 by the Catalina Sky Survey near Tucson, Arizona, and independently detected the next night by the Pan-STARRS 1 telescope, located on the summit of Haleakalā on Maui, Hawaii. Follow-up observations quickly confirmed the orbit of 2014 RC: it comes from just beyond the orbit of Mars.

The close appproach of this space rock offers researchers an opportunity for point-blank studies of a near-Earth asteroid. Even amateur astronomers will be able to track it. Around the time of closest approach, it will brighten to magnitude +11.5 as it zips through the constellation Pisces. This means it will be invisible to the naked eye but a relatively easy target for backyard telescopes equipped with CCD cameras. [ephemeris] [3D orbit]

According to NASA, "[the orbit of 2014 RC] will bring it back to our planet's neighborhood in the future. The asteroid's future motion will be closely monitored, but no future threatening Earth encounters have been identified."

MORE ASTEROID NEWS: While 2014 RC grabs headlines this weekend by flying under Earth's belt of geosynchronous satellites (see the news item below), astronomers are training their telescopes on another, weirder asteroid also in Earth's neighborhood. 2002 CE26 is a binary asteroid consisiting of a primary space rock 3.5 km in diameter and a secondary approximately one-tenth as wide. What's weird is, radar data suggest that the secondary space rock might have a moon of its own. Alberto Quijano Vodniza of the University of Narino Observatory in Colombia photographed the triple system streaking through the constellation Pegasus on Sept. 2nd:

At closest approach on Sept. 9th, 2002 CE26 will be 18.4 million km (0.123 AU) from Earth. That is relatively far away, but because of the asteroid's large size, it is still possible to obtain meaningful data from the flyby. NASA astronomers will be pinging the system using the Goldstone radar in the Mojave desert. The Goldstone team says "we should be able to get coarse-resolution images of the primary. Echoes from the secondary will be weak and on the edge of detectability."

They also encourage experienced amateur astronomers to monitor the flyby: "This object should reach 14th magnitude while at favorable solar elongations, so it should be an excellent target for lightcurves. Lightcurves might detect the signature of at least one satellite and could help refine the orbital period." [3D orbit] [ephemeris]

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.